It is proposed to study sperm agglutinating and sperm immobilizing antibodies and immunoglobulins in the cervical mucus of women with infertility problems and in control samples from normal women, and to improve the sperm antibody detection in these secretions. In all cases, the blood serum will be evaluated for the presence of agglutinating antibodies and correlated with the level of estradiol. Immobilization techniques and fluorescent antibody techniques will be further perfected and the agglutination methods adopted to a microscale. In later stages, the preparation of soluble antigens from spermatozoa is planned in order to develop precipitation methods with their antigens as a means of improving sperm specific antibody detection in cervical mucus. Some other related matters such as phagozytic activity in the cervical region, the influence of bacteria and mycoplasms, factors that prolong the viability of spermatozoa in cervical mucus, and studies on animal material such as bovine and rabbit cervical mucus are proposed.